28 U.S.C. § 133 — Appointment and number of district judges

(a) The President shall appoint, by and with the advice and consent of the Senate, district judges for the several judicial districts, as follows: (b)(1) In any case in which a judge of the United States (other than a senior judge) assumes the duties of a full-time office of Federal judicial administration, the President shall appoint, by and with the advice and consent of the Senate, an additional judge for the court on which such judge serves. If the judge who assumes the duties of such full-time office leaves that office and resumes the duties as an active judge of the court, then the President shall not appoint a judge to fill the first vacancy which occurs thereafter in that court. (2) For purposes of paragraph (1), the term "office of Federal judicial administration" means a position as Director of the Federal Judicial Center, Director of the Administrative Office of the United States Courts, or Counselor to the Chief Justice.